functions with bindings

code/code.go

@@ -35,6 +35,8 @@ const (
 	OpCall
 	OpReturnValue
 	OpReturn
+	OpGetLocal
+	OpSetLocal
 )
 
 type Definition struct {
@@ -67,6 +69,8 @@ var definitions = map[Opcode]*Definition{
 	OpCall:          {"OpCall", []int{}},
 	OpReturnValue:   {"OpReturnValue", []int{}},
 	OpReturn:        {"OpReturn", []int{}},
+	OpGetLocal:      {"OpGetLocal", []int{1}},
+	OpSetLocal:      {"OpSetLocal", []int{1}},
 }
 
 func Lookup(op byte) (*Definition, error) {
@@ -98,6 +102,8 @@ func Make(op Opcode, operands ...int) []byte {
 		switch width {
 		case 2:
 			binary.BigEndian.PutUint16(instruction[offset:], uint16(o))
+		case 1:
+			instruction[offset] = byte(o)
 		}
 		offset += width
 	}
@@ -151,6 +157,9 @@ func ReadOperands(def *Definition, ins Instructions) ([]int, int) {
 		switch width {
 		case 2:
 			operands[i] = int(ReadUint16(ins[offset:]))
+		case 1:
+			operands[i] = int(ReadUint8(ins[offset:]))
+
 		}
 
 		offset += width
@@ -162,3 +171,7 @@ func ReadOperands(def *Definition, ins Instructions) ([]int, int) {
 func ReadUint16(ins Instructions) uint16 {
 	return binary.BigEndian.Uint16(ins)
 }
+
+func ReadUint8(ins Instructions) uint8 {
+	return ins[0]
+}

code/code_test.go

@@ -10,6 +10,7 @@ func TestMake(t *testing.T) {
 	}{
 		{OpConstant, []int{65534}, []byte{byte(OpConstant), 255, 254}},
 		{OpAdd, []int{}, []byte{byte(OpAdd)}},
+		{OpGetLocal, []int{255}, []byte{byte(OpGetLocal), 255}},
 	}
 
 	for _, tt := range test {
@@ -30,13 +31,15 @@ func TestMake(t *testing.T) {
 func TestInstructions(t *testing.T) {
 	instructions := []Instructions{
 		Make(OpAdd),
+		Make(OpGetLocal, 1),
 		Make(OpConstant, 2),
 		Make(OpConstant, 65535),
 	}
 
 	expected := `0000 OpAdd
-0001 OpConstant 2
-0004 OpConstant 65535
+0001 OpGetLocal 1
+0003 OpConstant 2
+0006 OpConstant 65535
 `
 
 	concatted := Instructions{}
@@ -49,13 +52,14 @@ func TestInstructions(t *testing.T) {
 	}
 }
 
-func TestOperands(t *testing.T) {
+func TestReadOperands(t *testing.T) {
 	tests := []struct {
 		op        Opcode
 		operands  []int
 		bytesRead int
 	}{
 		{OpConstant, []int{65535}, 2},
+		{OpGetLocal, []int{255}, 1},
 	}
 
 	for _, tt := range tests {